application/hub/main/handler/tasks/class_TaskHandler.php

   1 <?php
   2 /**
   3  * A Task handler
   4  *
   5  * @author              Roland Haeder <webmaster@shipsimu.org>
   6  * @version             0.0.0
   7  * @copyright   Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2012 Hub Developer Team
   8  * @license             GNU GPL 3.0 or any newer version
   9  * @link                http://www.shipsimu.org
  10  *
  11  * This program is free software: you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation, either version 3 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23  */
  24 class TaskHandler extends BaseHandler implements Registerable, HandleableTask {
  25         // Exception constants
  26         const EXCEPTION_TASK_IS_INVALID = 0xb00;
  27
  28         /**
  29          * Protected constructor
  30          *
  31          * @return      void
  32          */
  33         protected function __construct () {
  34                 // Call parent constructor
  35                 parent::__construct(__CLASS__);
  36
  37                 // Set handler name
  38                 $this->setHandlerName('task');
  39         }
  40
  41         /**
  42          * Creates an instance of this class
  43          *
  44          * @return      $handlerInstance        An instance of a HandleableTask class
  45          */
  46         public static final function createTaskHandler () {
  47                 // Get new instance
  48                 $handlerInstance = new TaskHandler();
  49
  50                 // Output debug message
  51                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Initializing task handler.');
  52
  53                 // Init the task list
  54                 $handlerInstance->setListInstance(ObjectFactory::createObjectByConfiguredName('task_list_class'));
  55
  56                 // Get default instance
  57                 $handlerInstance->setIteratorInstance($handlerInstance->getListInstance()->getIterator());
  58
  59                 // Init visitor instance for faster loop
  60                 $handlerInstance->setVisitorInstance(ObjectFactory::createObjectByConfiguredName('active_task_visitor_class'));
  61
  62                 // Register the first (and generic) idle-loop task
  63                 $taskInstance = ObjectFactory::createObjectByConfiguredName('idle_task_class');
  64                 $handlerInstance->registerTask('idle_loop', $taskInstance);
  65
  66                 // Output debug message
  67                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Task handler initialized.');
  68
  69                 // Return the prepared instance
  70                 return $handlerInstance;
  71         }
  72
  73         /**
  74          * Tries to execute the given task. If as task should not be started (yet)
  75          * or the interval time (see task_interval_delay) is not yet reached the
  76          * task is quietly skipped.
  77          *
  78          * @return      void
  79          * @throws      InvalidTaskException    If the current task is invalid
  80          */
  81         private function executeCurrentTask () {
  82                 // Update no task by default
  83                 $updateTask = FALSE;
  84
  85                 // Is the current task valid?
  86                 if (!$this->getListInstance()->getIterator()->valid()) {
  87                         // Not valid!
  88                         throw new InvalidTaskException($this, self::EXCEPTION_TASK_IS_INVALID);
  89                 } // END - if
  90
  91                 // Get current task
  92                 $currentTask = $this->getListInstance()->getIterator()->current();
  93
  94                 // Is the task not yet started?
  95                 if ($currentTask['task_started'] === FALSE) {
  96                         // Determine difference between current time and registration
  97                         $diff = ($this->getMilliTime() - $currentTask['task_registered']) * 1000;
  98
  99                         // Should we start now?
 100                         if ($diff < $currentTask['task_startup_delay']) {
 101                                 // Skip this silently
 102                                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Task ' . $currentTask['id'] . ' not started: diff=' . $diff . ',task_startup_delay=' . $currentTask['task_startup_delay']);
 103                                 return;
 104                         } // END - if
 105
 106                         // Launch the task and mark it as updated
 107                         $currentTask['task_started'] = TRUE;
 108                         $updateTask = TRUE;
 109
 110                         // Debug message
 111                         self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Task ' . $currentTask['id'] . ' started with startup_delay=' . $currentTask['task_startup_delay'] . 'ms');
 112                 } // END - if
 113
 114                 // Get time difference from interval delay
 115                 $diff = ($this->getMilliTime() - $currentTask['task_last_activity']) * 1000;
 116
 117                 // Is the interval delay reached?
 118                 if ((($diff < $currentTask['task_interval_delay']) && ($currentTask['task_max_runs'] == 0)) || (($currentTask['task_total_runs'] == $currentTask['task_max_runs']) && ($currentTask['task_max_runs'] > 0))) {
 119                         // Should we update the task from startup?
 120                         if ($updateTask === TRUE) {
 121                                 // Update the task before leaving
 122                                 $this->updateTask($currentTask);
 123                         } // END - if
 124
 125                         // Skip this silently
 126                         return;
 127                 } // END - if
 128
 129                 // Set last activity
 130                 $currentTask['task_last_activity'] = $this->getMilliTime();
 131
 132                 // Count this run
 133                 $currentTask['task_total_runs']++;
 134
 135                 // Update the task
 136                 $this->updateTask($currentTask);
 137
 138                 // And visit/run it
 139                 // @TODO Messurement can be added around this call
 140                 $currentTask['task_instance']->accept($this->getVisitorInstance());
 141         }
 142
 143         /**
 144          * Updates given task by updating the underlaying list
 145          *
 146          * @param       $taskEntry      An array with a task
 147          * @return      void
 148          */
 149         private function updateTask (array $taskEntry) {
 150                 // Get the key from current iteration
 151                 $key = $this->getListInstance()->getIterator()->key();
 152
 153                 // Get the hash from key
 154                 $hash = $this->getListInstance()->getHash($key);
 155
 156                 // Update the entry
 157                 $this->getListInstance()->updateCurrentEntryByHash($hash, $taskEntry);
 158         }
 159
 160         /**
 161          * Unregisters the given task
 162          *
 163          * @param       $taskData       Data of the task
 164          * @return      void
 165          */
 166         private function unregisterTask (array $taskData) {
 167                 // Debug output
 168                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Removing task ' . $taskData['id'] . ' from queue - START');
 169
 170                 // Remove the entry
 171                 $this->getListInstance()->removeEntry('tasks', $taskData);
 172
 173                 // Debug output
 174                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Removing task ' . $taskData['id'] . ' from queue - FINISHED');
 175          }
 176
 177         /**
 178          * Registers a task with a task handler.
 179          *
 180          * @param       $taskName               A task name to register the task on
 181          * @param       $taskInstance   The instance we should register as a task
 182          * @return      void
 183          */
 184         public function registerTask ($taskName, Visitable $taskInstance) {
 185                 // Create the entry
 186                 $taskEntry = array(
 187                         // Identifier for the generateHash() method
 188                         'id'                  => $taskName,
 189                         // Whether the task is started
 190                         'task_started'        => FALSE,
 191                         // Whether the task is paused (not yet implemented)
 192                         'task_paused'         => FALSE,
 193                         // Whether the task can be paused (not yet implemented)
 194                         'task_pauseable'      => TRUE,
 195                         // Timestamp of registration
 196                         'task_registered'     => $this->getMilliTime(),
 197                         // Last activity timestamp
 198                         'task_last_activity'  => 0,
 199                         // Total runs of this task
 200                         'task_total_runs'     => 0,
 201                         // Task instance itself
 202                         'task_instance'       => $taskInstance,
 203                         // Startup delay in milliseconds
 204                         'task_startup_delay'  => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_startup_delay'),
 205                         // Interval time (delay) in milliseconds before this task is executed again
 206                         'task_interval_delay' => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_interval_delay'),
 207                         // How often should this task run?
 208                         'task_max_runs'       => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_max_runs'),
 209                 );
 210
 211                 // Add the entry
 212                 $this->getListInstance()->addEntry('tasks', $taskEntry);
 213
 214                 // Debug message
 215                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Task registered: taskName=' . $taskName .
 216                         ' (taskInstance=' . $taskInstance->__toString() . ')' .
 217                         ', startupDelay=' . $taskEntry['task_startup_delay'] . 'ms' .
 218                         ', intervalDelay=' . $taskEntry['task_interval_delay'] . 'ms' .
 219                         ', maxRuns=' . $taskEntry['task_max_runs'] . ' ...'
 220                 );
 221         }
 222
 223         /**
 224          * Checks whether tasks are left including idle task
 225          *
 226          * @return      $tasksLeft      Whether there are tasks left to handle
 227          */
 228         public function hasTasksLeft () {
 229                 // Do we have tasks there?
 230                 $tasksLeft = (($this->getListInstance() instanceof Listable) && ($this->getListInstance()->count() > 0));
 231
 232                 // Return result
 233                 return $tasksLeft;
 234         }
 235
 236         /**
 237          * Handles all tasks by checking if they should startup or if it is their
 238          * turn to run. You should use this method in a while() loop in conjuntion
 239          * with hasTasksLeft() so you can e.g. shutdown by adding a ShutdownTask
 240          * which will attempt to remove all tasks from the task handler.
 241          *
 242          * @return      void
 243          */
 244         public function handleTasks () {
 245                 // Should we rewind?
 246                 if (!$this->getListInstance()->getIterator()->valid()) {
 247                         // Rewind to the beginning for next loop
 248                         $this->getListInstance()->getIterator()->rewind();
 249                 } // END - if
 250
 251                 // Try to execute the task
 252                 $this->executeCurrentTask();
 253
 254                 // Go to next entry
 255                 $this->getListInstance()->getIterator()->next();
 256         }
 257
 258         /**
 259          * Shuts down all tasks and the task handler itself. This method should be
 260          * called from a corresponding filter class.
 261          *
 262          * @return      void
 263          */
 264         public function doShutdown () {
 265                 // Always rewind to the beginning for next loop
 266                 $this->getListInstance()->getIterator()->rewind();
 267
 268                 // Debug message
 269                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Shutting down all ' . $this->getListInstance()->count() . ' tasks...');
 270
 271                 // Remember all tasks that has been shutdown for removal
 272                 $tasks = array();
 273
 274                 // Instance a visitor
 275                 $this->setVisitorInstance(ObjectFactory::createObjectByConfiguredName('shutdown_task_visitor_class'));
 276
 277                 // Shutdown all tasks in once go
 278                 while ($this->getListInstance()->getIterator()->valid()) {
 279                         // Get current entry
 280                         $currentTask = $this->getListInstance()->getIterator()->current();
 281
 282                         // Output debug message
 283                         self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Shutting down task ' . $currentTask['id'] . ' (taskInstance=' . $currentTask['task_instance']->__toString() . ') ...');
 284
 285                         // Shutdown the task
 286                         $currentTask['task_instance']->accept($this->getVisitorInstance());
 287
 288                         // Remember this task
 289                         array_push($tasks, $currentTask);
 290
 291                         // Advance to next one
 292                         $this->getListInstance()->getIterator()->next();
 293                 } // END - while
 294
 295                 // Debug message
 296                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Shutdown of all tasks completed.');
 297
 298                 // Remove all tasks
 299                 foreach ($tasks as $entry) {
 300                         $this->unregisterTask($entry);
 301                 } // END - foreach
 302         }
 303 }
 304
 305 // [EOF]
 306 ?>